1. Field of the Invention
The present invention relates to a sheet conveying apparatus for conveying a plurality of sheets, and a book binding apparatus for book binding a sheet bundle including a plurality of sheets.
2. Description of the Related Art
Recently, image forming apparatuses of the electrophotographic and inkjet type have been improved in speed and image quality, so that such an inkjet or electrophotographic image forming apparatus becomes able to produce a printed matter that a large-sized printing press has only been able to make.
The large-sized printing press only prints images on sheets, and after treatment, such as stapling and book binding, employs a different special purpose machine. Also, the large-sized printing press is suitable for printing a large number of printed matters in view of cost and plate making time.
Whereas, the inkjet or electrophotographic image forming apparatus can connect a plurality of after treatment machines thereto, so that it is advantageous to be able to carry through the process from the printing to the after processing with one apparatus. The inkjet or electrophotographic image forming apparatus is also suitable for printing the small number of printed matters in comparison with the large-sized printing press.
On the other hand, a configuration of a book binding apparatus arranged between an image forming apparatus and an after treatment device is disclosed in Japanese Patent Laid-Open No. 2005-335909. In this configuration, when a sheet outputted from the image forming apparatus is conveyed through to the after treatment device, the book binding apparatus receives the sheet from the image forming apparatus arranged upstream in the conveying direction so as to transfer the sheet to the after treatment device on the downstream side.
The book binding apparatus disclosed in Japanese Patent Laid-Open No. 2005-335909 includes a conveying path used during book binding and another conveying path intersecting with the conveying path for transferring a sheet to the after treatment device so as to achieve the miniaturization and the space saving.
However, during the book binding in the book binding apparatus or during conveying the book bound sheet bundle onto a sheet loading tray, the sheet may not be conveyed to the after treatment device on the downstream side because of the intersection of the conveying paths. That is, when the job transferring the sheet to the after treatment device is executed in succession to the book binding job in the book binding apparatus, the sheet bundle bound by the book binding apparatus may collide on a sheet to be conveyed to the after treatment device on the downstream side so as to generate sheet jamming. For solving this problem, the job transferring the sheet to the after treatment device may be waited until the book binding processing is completely finished. However the productivity may be deteriorated.